A wireless communication device, such as a mobile phone device or a smart phone, may include two or more Subscriber Identity Modules (SIMs). Each SIM may enable at least one subscription via a Radio Access Technology (RAT). Such a wireless communication device may be a multi-SIM wireless communication device. In a Multi-SIM-Multi-Active (MSMA) wireless communication device, all SIMs may be active at the same time. In a Multi-SIM-Multi-Standby (MSMS) wireless communication device, if any one SIM is active, then the rest of the SIM(s) may be in a standby mode. The RATs may include, but are not limited to, Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA) (particularly, Evolution-Data Optimized (EVDO)), Universal Mobile Telecommunications Systems (UMTS) (particularly, Wideband Code Division Multiple Access (WCDMA), Long Term Evolution (LTE), High-Speed Downlink Packet Access (HSDPA), and the like), Global System for Mobile Communications (GSM), Code Division Multiple Access 1× Radio Transmission Technology (1×), General Packet Radio Service (GPRS), Wi-Fi, Personal Communications Service (PCS), and other protocols that may be used in a wireless communications network or a data communications network.
A multi-SIM wireless communication device (e.g., a MSMS wireless communication device) may employ a Discontinuous Reception (DRX) mode to conserve power. The wireless communication device may be in a Connected DRX (CDRX) mode while in a Radio Resource Control (RRC)-connected state, as per Release 8, 3rd Generation Partnership Project (3GPP). For example, when the wireless communication device is not engaged in active data transfer on a first subscription, a network associated with the first subscription may configure the first subscription of the wireless communication device to be in the CDRX mode. For example, a base station (e.g., an evolved Node B (eNodeB)) of the network of the first subscription may configure the wireless communication device into the CDRX mode. In a cycle of the CDRX mode, the wireless communication device may be awake (engaged in activities with Radio Frequency (RF) resources of the wireless communication device) for a period of time (e.g., an awake period or “on duration”) for monitoring a Physical Downlink Shared Channel (PDSCH). Within the same cycle, the wireless communication device may sleep (not engaged in reception activities by idling the RF resource) for a period of time (e.g., a sleep period or “off duration”) to conserve power. Accordingly, in response to the wireless communication device receiving any downlink data indicated by the PDSCH from the network in the awake period, the wireless communication device may abandon the CDRX mode and continuously monitor the PDSCH for downlink data (e.g., continuous reception); otherwise, the wireless communication device may sleep in the sleep period to avoid power consumption.
In some instances, activities of a second subscription of the multi-SIM wireless communication device may occur during the awake period or inactivity timer duration of the first subscription. Such activities may include page decoding or other idle-mode activities of the second subscription. Given that idle-mode activities of the second subscription may have priority over first subscription activities in the awake period or in the inactivity timer duration, the wireless communication device may not decode the PDSCH for the first subscription if the first subscription awake period or the inactivity timer duration overlaps with the time the activities of the second subscription occur. Thus, if the network allocates downlink data for the first subscription in the PDSCH and the corresponding portion of the first subscription awake period or inactivity timer duration collides with the time the activities of the second subscription occur, the first subscription may not be able to decode the allocated downlink data.
To recover missed downlink data, the wireless communication device may attempt to decode in a next CDRX cycle. However, a successful recovery attempt may be contingent upon the time the activities of the second subscription occur not colliding with the awake period of the first subscription and validities of L1/Radio Link Control (RLC) level retransmission. Repeated overlap between the awake periods (or inactivity timer duration) of the first subscription and the time the activities of the second subscription occur may result in repeated failure to decode allocated downlink data on the first subscription, thus negatively impacting the user experience due to inefficiency.